An optoelectronic component of the kind mentioned in the introductory part of the description is known, for example from U.S. Pat. No. 5,347,605. The optoelectronic component may, for example, be connectable to a light guide. The optoelectronic element may, for example, be a light-emitting diode (LED) which emits light in the light guide, or a photodetector which detects light from the light guide.
From the above-mentioned patent it is known to arrange an LED adjustably in relation to the light guide when mounting the optoelectronic component. The symmetry axis and the optical axis of the LED coincide approximately with the longitudinal axis of the light guide. The housing comprises a body with a cylindrical recess. The LED is surrounded by a mounting body in the form of a ring with a double-curved envelope surface. The envelope surface has a spherical shape with a diameter which coincides with the diameter of the recess. When mounting the component, the light guide is first mounted in the housing, whereupon the LED with a mounting ring is pushed a certain distance into the recess and is connected to a current source. The intensity of the light emitted from the far end of the light guide is measured. By rotating and axially displacing the LED with the mounting ring in the recess, it can be adjusted so as to obtain a maximum intensity value. In this position, the LED is mechanically locked to the housing with the aid of a fast-curing resin, whereafter the gap between the ring and the recess is filled having a resin with a high mechanical stability, for example epoxy resin.
One disadvantage of using resin for joining together the LED and the housing is that there is a certain risk of the joint leaking moisture or other gases. Another disadvantage is that the resin must cure for a certain time before the component endures movement, which in turn extends the mounting time. It is, therefore, desirable to join the LED and the housing together by means of a welded joint. The advantages of a welded joint are that it is completely tight, has a high mechanical strength, and needs no curing time.
When the LED, provided with a mounting ring, is to be welded to the recess, the problem arises as to where to place a welded joint. To make the welding possible, the distance between two points to be welded must not exceed a maximum distance. Since the LED with the mounting ring is inserted a certain distance into the recess, the distance from the opening edge of the recess to that point where the distance between the mounting ring and the recess is lower than the maximum distance becomes too large to make access to welding possible (see FIG. 5 in the above-mentioned patent). The adjustment of the LED along its symmetry axis also causes problems since the position of the welded joint will vary between different components.
To avoid the above-mentioned problems, attempts were made to mount the LED directly in the recess without the mounting ring. This led to the creation of a space between the LED and the recess, which made possible adjustment of the LED in directions perpendicular to its symmetry axis. That end of the LED which faces away from the light guide has a flange which runs around the whole LED. After the adjustment, the opening edge of the recess and the flange of the LED were welded to each other. However method this mounting does not provide for any axial displacement of the LED and hence for no adjustment of the LED in relation to the light guide in the axial direction. It was found that this gave such a poor adjustment of the LED that a majority of the mounted components had to be rejected. The conclusion is that an adjustment of the LED in the axial direction is necessary to obtain an acceptable luminous efficiency between the LED and the light guide.
The present invention aims to solve the problem as to how to join an optoelectronic semiconductor element provided with a mounting ring, using a method of mounting comprising adjustment of the optoelectronic semiconductor element in the axial direction, to a recess in a body to obtain a completely tight joint.